basic wiring help please

[Brandy]

Hi everyone. I have a '70 240Z, manual trans, pretty stock. Prior owner had pretty much neglected it (left it sitting in a garage), then jerryrigged some stuff, painting other stuff black before selling it to an unsuspecting buyer (um..me).

Since then, I've had the carbs remanufactured, ingnition coil replaced, voltmeter cleaned up, gas tank dropped and cleaned, and now I'm tackling the electrical stuff (BTW, I'm a Biologist, not a mechanic or engineer, but I'm willing to learn, which is a big reason I got this car).

This car runs really nice now, and outside of placing insulation padding under the carpet (that topic is another thread), possibly replacing the air cleaner set (another thread) and replacing the weatherstripping on both windshield and rear hatch when I get the car repainted next year, am pretty much done for now. Except for scary electricals.

I have interior lights (replaced all the bulbs under the dash; glad I'm limber and have small hands), front headlights, brake lights, directionals and hazard lights. But when I need the running lights (for nighttime driving), I get nothing, and also don't have the rear side marker lights (but they work for directionals and hazards). And another odd thing, whenever I brake, the front directionals also blink on). I've been tracing the wires, and have been removing the duct tape covering the wires, cleaning the wires and reattaching them. The PO apparently had been given a solder for a present and had gone to town on the wires, but doing a pretty messy job soldering wires together. The harness under the front hood in front of the radiator is a mess. Before he went out to sea, my husband, a maritime engineer, checked all the fuses, replaced some, and had been checking out the wires for voltage. The wires on the steering column switches have also been replaced and soldered together.

Any idea where I could be making a spooky process even worse, or am I going the right way, slowly tracing out lines, or should I just get replacement harnesses? I have no problem driving the car as is, but in the instances where I would be out late, driving without taillights at night is not a prospect I relish.

I'm debating whether I should just replace both harnesses.

[kmack]

Any idea where I could be making a spooky process even worse, or am I going the right way, slowly tracing out lines, or should I just get replacement harnesses? I have no problem driving the car as is, but in the instances where I would be out late, driving without taillights at night is not a prospect I relish.

I'm debating whether I should just replace both harnesses.

Hey, Brandy. Good to hear that you're at least driving the car during the day!

Do you have a wiring diagram like the one in the Haynes manual? If so, does it make sense? Otherwise, yes you could maybe make things worse. I don't mean to scare.

Wiring diagrams are fairly easy to read, but you have to understand some the reasoning behind the processes for it all to make sense. Get a diagram and then start by making sure that the right colored wires are going to all the right places. If some of the wires have been replaced (w/ different colors), then you may be in for a world of hurt.

Based on your current description of the harnesses "rehabilitation" by the PO, you might be better off trying to find used harnesses. The unfortunate side is that you have a very early car. For the most part, all the 240Z harnesses are wired up the same (a few minor differences for extra emissions stuff like on the '73s), but the big difference is in the connector plug types. Example: a '73 rear harness may be wired exactly like one from a '71, but because of the connector types, they won't plug into each other.

I had this exact same issue (although not to the same degree as you) when I rebuilt my car. The '73 harnesses were in much better condition than my '71, but I couldn't mix-n-match.

I would start the search for a good clean set of harnesses for your year model (or early '71, before 6/71). If that can't be found, get a hold of, or borrow, a set of harnesses for whatever year 240 you can find. What you'll need to do is lay the two harnesses out next to each other and compare. Then fix all the things that look wrong (based on a wiring diagram) with your harness. It will mean pulling the dash completely out and lots of time spent on the floor. But when it's done, it'll also mean you can drive at night!

[Brandy]

Hi Ken - (BTW, Danny says hi). I was able to get a pair of used early 70-72 harnesses online, and with a FSM on its way from Courtesy, hope that it shouldn't be too hard to trace out. The Haynes manual is great, but I've had to teach myself how to read schematics now that hubby (engineer) is away, plus the PO did improvise quite a few of the wires (he actually replaced the wire connecting the ignition module thingy to the distributor with a 4 foot long wire that looked as it came straight from a stereo system.). Needless to say, if the hex I did on him is working, he should have special body parts falling off by now.

I'm pretty patient, and have no qualms sitting in the open hatchback for hours tracing wires, or replacing the setup, so hopefully all this poor little car needs is a new necklace of electrics. Otherwise, I'll driver her up to 'visit' your area during the next car club meeting and perhaps you can help....;-)

[EScanlon]

I have interior lights (replaced all the bulbs under the dash; glad I'm limber and have small hands), ...

Quit your bragging!

... front headlights, brake lights, directionals and hazard lights. But when I need the running lights (for nighttime driving), I get nothing, and also don't have the rear side marker lights (but they work for directionals and hazards). And another odd thing, whenever I brake, the front directionals also blink on).

Your SIDE markers should NEVER be lit unless the driving lights are on. This applies regardless of front or rear.

That they operate in response to the turn and hazards, and also to the brake circuit, tell me that someplace a wire has been connected incorrectly.

Since you mention that the IPO had made some creative fixes, I'll mention that that is the reason I replaced all of my dash wiring to correct the errors in mine. That being said, it isn't impossible to repair a bunged up wiring harness, but it might be a very long and extremely tedious process. Replacing the harness will make it much easier to correct problems without introducing new ones.

You also need to be aware of some production differences between the wiring harnesses. That your car is an early Z with a stick will make it easier than if it were an auto, ( AT's have a kick-down circuit as well as a Neutral cut-out. Not sure as to the neutral switch in a manual.) It has the least or no smog equipment that was wired in.

If you need some help, I'll try to give a hand.

Enrique